The goal is to develop an instrument for safe, quick, anesthesia- free measurement of intraocular pressure through the lower eyelid. Pressure is indicated by resonant properties of the eyeball. A low-frequency exciter vibrates the eyelid, vibrational energy flow from the exciter is measured, and elicited eyeball responses are measured by ultrasound. Data analysis spanning frequency and pressure variations yields a reliable estimate of intraocular pressure and its time variations. Project objectives are to demonstrate an instrument on a mechanical eyeball analogue, obtain accuracy data and determine required eye exposure to low-frequency vibrations and ultrasound energy, in order to evaluate human safety.